Printer, server and non-transitory computer-readable recording media storing computer readable instructions for printer and server

ABSTRACT

A first printer may include a controller configured to: in a case where a first predetermined operation is accepted in a state where second printer identification information and specific service-related information are stored in association with each other in the server, cause the display unit to display a notification screen that prompts a second predetermined operation, the second predetermined operation being for changing a printer used for the service from a second printer to the first printer; and in a case where the second predetermined operation is accepted, send a printer changing request including first printer identification information to the server. In a case where the printer changing request is sent to the server, the first printer identification information is stored, instead of the second printer identification information, in association with the specific service-related information in the server.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.17/216,912, filed on Mar. 30, 2021, which is claims priority to JapanesePatent Application No. 2020-065911, filed on Apr. 1, 2020, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The disclosure herein discloses a technique in which a server provides aservice using a printer.

BACKGROUND

A printer capable of executing a flat-rate printing process is known.With the flat-rate printing process, the printer prints a predeterminednumber of sheets at a fixed rate every predetermined period.

SUMMARY

The above technique does not give any consideration to changing theprinter used for the flat-rate printing process. The disclosure hereinprovides a technique that enables a printer used for a service to bechanged.

A first printer disclosed herein may include: a display unit; acommunication interface for communicating with a server, wherein theserver is configured to store, for each of one or more printers, printeridentification information for identifying the printer andservice-related information for providing a service using the printer inassociation with each other, the service-related information beingobtained by using information received from the printer; and acontroller. The controller may be configured to: in a case where a firstpredetermined operation is accepted in a state where second printeridentification information for identifying a second printer and specificservice-related information are stored in association with each other inthe server, cause the display unit to display a notification screen thatprompts a second predetermined operation, the second printer beingdifferent from the first printer, and the second predetermined operationbeing for changing a printer used for the service from the secondprinter to the first printer; and in a case where the secondpredetermined operation is accepted after the notification screen hasbeen displayed, send a printer changing request including first printeridentification information for identifying the first printer to theserver via the communication interface, wherein in a case where theprinter changing request is sent to the server, the first printeridentification information included in the printer changing request isstored, instead of the second printer identification information, inassociation with the specific service-related information in the server.

Also, a server disclosed herein may include a communication interfacefor communicating with a printer; a memory configured to store, for eachof one or more printers, printer identification information foridentifying the printer and service-related information for providing aservice using the printer in association with each other, theservice-related information being obtained by using information receivedfrom the printer; and a controller. The controller may be configured to:in a state where second printer identification information foridentifying a second printer and specific service-related informationare stored in association with each other in the memory, receive aprinter changing request from a first printer via the communicationinterface, the first printer being different from the second printer,the printer changing request including first printer identificationinformation for identifying the first printer; and in a case where theprinter changing request is received from the first printer, store thefirst printer identification information included in the printerchanging request, instead of the second printer identificationinformation, in association with the specific service-relatedinformation.

A computer program and a non-transitory computer-readable medium storingcomputer readable instructions for the first printer are also novel anduseful. A computer program and a non-transitory computer-readable mediumstoring computer readable instructions for the server are also novel anduseful. Methods carried out by the first printer and the server are alsonovel and useful. Moreover, a communication system comprising the firstprinter and the server is also novel and useful.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a configuration of a communication system;

FIG. 2 shows a sequence diagram of a printer registration process;

FIG. 3 shows a sequence diagram according to a first embodiment;

FIG. 4 shows a sequence diagram continued from FIG. 3 ;

FIG. 5 shows a sequence diagram according to a second embodiment;

FIG. 6 shows a sequence diagram according to a third embodiment; and

FIG. 7 shows a sequence diagram according to a fourth embodiment.

DETAILED DESCRIPTION First Embodiment Configuration of CommunicationSystem 2; FIG. 1

As shown in FIG. 1 , a communication system 2 includes a server 10, aterminal 50, and a plurality of printers 100 and 200. The printer 200and the terminal 50 are connected to a Local Area Network (LAN) 4. TheLAN 4 may be either a wired LAN or a wireless LAN. In the presentembodiment, in such situation, a user additionally connects the printer100 to the LAN 4. Consequently, the devices 50,100, and 200 becomecommunicable with one another via the LAN 4. For example, the terminal50 can cause a printer (e.g., 100) to execute printing by instructingthe printer to do so via the LAN 4.

The LAN 4 is connected to the Internet 6. The server 10 is installed onthe Internet 6. The server 10 is a server for providing a flat-rateprinting service. The server 10 is communicable with the devices 50,100,and 200 via the Internet 6.

The flat-rate printing service is a service that allows printing to apreset number (e.g., 200) of print medium at a fixed rate everypredetermined period (e.g., every month). The present embodimentassumes, particularly, that a printer used for the flat-rate printingservice is changed from the printer 200 to the printer 100.

Here, the flat-rate printing service using a printer is different, asdescribed below, from a flat-rate communication service using a generalmobile phone (i.e., a service allowing communication of a preset amountof data at a fixed rate). For the flat-rate printing service, the serverneeds to regularly receive information on the number of printed sheetsfrom the printer in order to manage the number of sheets related toprinting. On the other hand, for the flat-rate communication service,the server does not need to receive information on the amount of datafrom the mobile phone because the communication in the mobile phone isexecuted via the server. Because of the difference, a mechanism forchanging a printer used for the flat-rate printing service is differentfrom a mechanism for changing a mobile phone used for the flat-ratecommunication service. The following describes a technique that enablesa printer used for the flat-rate printing service to be changedappropriately.

Configuration of Printer 100

The printer 100 is a peripheral device (i.e., a peripheral device of theterminal 50, etc.) configured to execute a print function. The printer100 may be a multi-function device configured to execute a scanfunction, a FAX function, and the like, in addition to the printfunction. A printer ID “AAA”, which is information for identifying theprinter 100, is assigned to the printer 100.

Once a cartridge containing a color material (hereinafter, a cartridgewill be simply referred to as “CTG”) is mounted on the printer 100, theprinter 100 can execute printing by using the color material. In thepresent embodiment, the printer 100 is configured to use both asingle-purpose CTG for receiving the flat-rate printing service and ageneral-purpose CTG different from the single-purpose CTG. For example,once a flat-rate printing service contract has been concluded by a user,the single-purpose CTG is sent to the user from a vendor of the printer100 or a business entity associated with the vendor. The general-purposeCTG is a generally distributed CTG that the user can purchase at a homeappliance store, by mail order, or the like, for example.

The printer 100 includes an operation unit 112, a display unit 114, aprint executing unit 116, a communication interface (hereinafter, aninterface will be denoted as “I/F”) 120, and a controller 130. The units112 to 130 are connected to a bus line (reference sign omitted). Theoperation unit 112 includes a plurality of keys. The user can inputvarious instructions to the printer 100 by operating the operation unit112. The display unit 114 is a display configured to display variousinformation. The communication I/F 120 is an I/F configured to executecommunication and is connected to the LAN 4.

The print executing unit 116 includes a print mechanism of ink jetscheme or laser scheme. A CTG containing color material, such as ink,toner, or the like, is mounted on the print executing unit 116. The CTGis provided with an IC chip, and the print executing unit 116 includes areader (not shown) configured to read information in the IC chip. In theIC chip of the single-purpose CTG, single-purpose information (e.g., apredetermined code), which indicates that the CTG is the single-purposeCTG, is described. In the IC chip of the general-purpose CTG, thesingle-purpose information is not described. Therefore, when a CTG ismounted, the printer 100 can determine whether the CTG is thesingle-purpose CTG or the general-purpose CTG by reading the informationin the IC chip of the CTG.

The controller 130 includes a CPU 132 and a memory 134. The CPU 132 isconfigured to execute various processes according to a program 136stored in the memory 134. The memory 134 is configured of a volatilememory, a non-volatile memory, and the like. The memory 134 stores aservice mode flag 138 and a cumulative number of sheets (which will betermed “cumulative sheet number” hereinbelow).

The service mode flag 138 indicates a flag value of either “ON” or“OFF”. The printer 100 is configured to operate selectively in any oneof a plurality of operation modes including a mode in which the printer100 is capable of executing printing by using the single-purpose CTG anda mode in which the printer 100 is capable of executing printing byusing the general-purpose CTG but incapable of executing printing byusing the single-purpose CTG. In the following description, the formermode and the latter mode will be termed “service mode ON” and “servicemode OFF”, respectively. When the operation mode of the printer 100 isthe service mode ON, the service mode flag 138 indicates “ON”, whilewhen the operation mode of the printer 100 is the service mode OFF, theservice mode flag 138 indicates “OFF”. The cumulative sheet number is acumulative number of sheets of print medium printed by using thesingle-purpose CTG.

The printer 100 regularly sends information indicating the cumulativesheet number to the server 10. Thus, the server 10 can know the totalnumber of printed sheets within the predetermined period based on thecumulative sheet number, and can provide the flat-rate printing service.Further, the printer 100 also regularly sends information indicating aremaining amount of the color material in the single-purpose CTG and thelike to the server 10, although detailed description with drawings isomitted for that. Thus, when detecting that the remaining amount is lessthan a threshold, the server 10 can execute a process for shipping a newsingle-purpose CTG to the user.

Configuration of Printer 200

A printer ID “BBB” is assigned to the printer 200. The printer 200includes an operation unit 212, a display unit 214, a print executingunit 216, a communication I/F 220, and a controller 230. The controller230 includes a CPU 232 and a memory 234. The memory 234 stores a program236, a service mode flag 238, and a cumulative sheet number. Theseconfigurations are the same as the corresponding configurations of theprinter 100.

Configuration of Terminal 50

The terminal 50 is, for example, a portable terminal device such as amobile phone, a smart phone, a PDA, a tablet PC, or the like. In avariant, the terminal 50 may be a stationary PC, a notebook PC, or thelike. The terminal 50 includes a camera, an application for executingcommunication via the Internet 6 (e.g., a browser), an application forexecuting email communication (e.g., a mailer), and an application fordecoding a QR Code (registered trademark).

Configuration of Server 10

The server 10 is installed on the Internet 6 by the vendor of theprinter 100, 200. In a variant, the server 10 may be installed on theInternet 6 by a business entity different from the vendor.

The server 10 includes a communication I/F 20 and a controller 30. Theunits 20 to 30 are connected to a bus line (reference sign omitted). Thecommunication I/F 20 is connected to the Internet 6. The controller 30includes a CPU 32 and a memory 34. The CPU 32 is configured to executevarious processes according to a program 36 stored in the memory 34. Thememory 34 is configured of a volatile memory, a non-volatile memory, andthe like. The memory 34 stores a user table 38 and a sheet number table40.

The user table 38 stores a user ID for identifying a user, a password(which will be simply denoted as “PW” hereinbelow), and a printer ID inassociation with each other. These pieces of information are stored inthe user table 38 through a process of FIG. 2 to be described later. Inthe following description, a user ID and a PW may be collectivelyreferred to as “account information”.

The sheet number table 40 stores a printer ID, a cumulative sheet numberof the printer identified by the printer ID, an upper limit sheetnumber, and a current number of printed sheets (which will be termed“current sheet number” hereinbelow) in association with each other. Theupper limit sheet number is an upper limit of the number of printedsheets allowed within the predetermined period in the flat-rate printingservice. The current sheet number is the number of actually printedsheets within the predetermined period. These pieces of information arestored in the sheet number table 40 through the process of FIG. 2 or aprocess of FIG. 4 to be described later.

Printer Registration Process; FIG. 2

Next, a registration process for registering information related to theprinter 200 in the server 10 will be described with reference to FIG. 2. In an initial state of FIG. 2 , the operation mode of the printer 200is the service mode OFF. That is, the printer 200 is incapable ofexecuting printing by using the single-purpose CTG. Further, in theinitial state of FIG. 2 , the server 10 has already stored a user ID“XXX” and a PW “YYY” in association with each other in the user table38. The user accesses the server 10 by using, for example, the terminal50 to register these pieces of information (i.e., account information)in advance in the server 10.

In the following description, for easier understanding, processesexecuted by a CPU (e.g., the CPU 32) of each device (e.g., the server10) will be described with each device (e.g., the server 10) as thesubject of action, without describing the CPU as the subject of action.Further, every communication executed by the server 10 and the printers100, 200 to be described below is executed via the communication I/Fs20, 120, and 220. Therefore, in the following description, phrase “viathe communication I/F 20 (or 120, 220)” will be omitted for explanationof processes related to communication.

When accepting, from the user, a login operation including designationof a Uniform Resource Locator (URL) of the server 10 and input ofaccount information (i.e., the user ID “XXX” and the PW “YYY”) in T10,the terminal 50 sends the account information to the server 10 in T12.

When receiving the account information from the terminal 50 in T12, theserver 10 executes account authentication in T14. Specifically, theserver 10 determines whether the received account information is in theuser table 38 or not. In the present embodiment, the server 10determines that the received account information is in the user table 38(i.e., determines that the account authentication is successful), andexecutes subsequence processes from T16. The server 10 sendsregistration information screen data to the terminal 50 in T16.

When receiving the registration information screen data from the server10 in T16, the terminal 50 displays a registration information screenSC0 represented by the registration information screen data in T18. Theregistration information screen SC0 includes a message that asks whetherto register a printer, a registration button, and a cancel button. Whenaccepting selection of the registration button in the registrationinformation screen SC0 in T20, the terminal 50 sends a PIN code requestto the server 10 in T22.

When receiving the PIN code request from the terminal 50 in T22, theserver 10 generates a PIN code “C” in T24 and stores the PIN code “C” tothe memory 34 in association with the account information (i.e., theuser ID “XXX” and the PW “YYY”) that has been successfully authenticatedin T14. In T26, the server 10 sends the PIN code “C” generated in T24 tothe terminal 50.

When receiving the PIN code “C” from the server 10 in T26, the terminal50 displays the PIN code “C” in T28. As a result, the user can know thePIN code “C”.

When accepting input of the PIN code “C” from the user in T30, theprinter 200 sends a registration request to the server 10 in T40. Theregistration request includes the printer ID “BBB” of the printer 200and the PIN code “C” inputted in T30.

When receiving the registration request from the printer 200 in T40, theserver 10 stores the printer ID “BBB” included in the registrationrequest into the user table 38 and the sheet number table 40 in T42.Specifically, the server 10 firstly identifies, from the user table 38,the account information (i.e., the user ID “XXX” and the PW “YYY”)stored in association with the PIN code “C” included in the registrationrequest. Then, the server 10 stores the printer ID “BBB” to the usertable 38 in association with the identified account information.Further, the server 10 stores the printer ID “BBB”, a cumulative sheetnumber “0”, a preset upper limit sheet number “200”, and a current sheetnumber “0” in association with each other into the sheet number table40.

After that, information (e.g., an access token) for establishing anExtensible Messaging and Presence Protocol (XMPP) connection, which isso-called full-time connection, between the server 10 and the printer200 is communicated, as a result of which an XMPP connection isestablished between the server 10 and the printer 200 in T50. By usingthe XMPP connection, the server 10 can send signals to the printer 200beyond the firewall of the LAN 4 to which the printer 200 belongs,without receiving requests from the printer 200.

The server 10 then sends a mode changing request to the printer 200 inT52 by using the XMPP connection. The mode changing request is a signalthat requests the operation mode of the printer 200 to be changed fromthe service mode OFF to the service mode ON.

When receiving the mode changing request from the server 10 in T52, theprinter 200 changes the service mode flag 238 from OFF to ON in T54.That is, the operation mode of the printer 200 is set to the servicemode ON. As a result, the printer 200 can be used to provide theflat-rate printing service to the user. In this case, the printer 200stores “0” as the cumulative sheet number.

When the registration request is sent to the server 10 in T40, theserver 10 executes a process for shipping the single-purpose CTG to theuser of the printer 200. Therefore, the user can receive thesingle-purpose CTG. In T60, the single-purpose CTG is mounted to theprinter 200. At this time, the printer 200 can know that thesingle-purpose CTG has been mounted by reading information in the ICchip of the single-purpose CTG. The printer 200 updates the cumulativesheet number in the memory 234 each time it executes printing by usingthe single-purpose CTG mounted thereon. Since the operation mode of theprinter 200 is the service mode ON (i.e., the service mode flag 238 isON) when the single-purpose CTG is mounted to the printer 200, theprinter 200 does not display a notification screen SC1 (see FIG. 3 ),which will be described later. It is possible to prevent the screen frombeing unnecessarily displayed.

The printer 200 executes printing by using the single-purpose CTG in T62and updates the cumulative sheet number in the memory 234. In thepresent embodiment, the printing is executed to 50 sheets of printmedium in T62, therefore, “50” is stored as the cumulative sheet number.When a predetermined timing (for example, a predetermined time of theday) arrives, the printer 200 sends a notification including the printerID “BBB” and the cumulative sheet number “50” in the memory 234 to theserver 10 in T70.

When receiving the notification from the printer 200 in T70, the server10 updates the sheet number table 40 in T80. Specifically, the server 10firstly identifies, from the sheet number table 40, the cumulative sheetnumber “0” and the current sheet number “0” associated with the printerID “BBB” included in the notification of T70. Next, the server 10calculates a difference “50” between the identified cumulative sheetnumber (in the present case, “0”) and the cumulative sheet number “50”included in the notification of T70. Then, the server 10 updates thecurrent sheet number by adding the difference “50” to the identifiedcurrent sheet number (in the present case, “0”). The server 10 furtherupdates the identified cumulative sheet number (in the present case,“0”) to the cumulative sheet number “50” included in the notification ofT70. The processes of T70 and T80 are executed regularly (e.g., everyday).

Printer Change; FIGS. 3 and 4

Next, with reference to FIGS. 3 and 4 , a process for changing theprinter used for the flat-rate printing service from the printer 200 tothe printer 100 will be described. In the following description, theprinter used for the flat-rate printing service may be referred to as“service-target printer”. FIG. 3 is a continuation of FIG. 2 , where theoperation mode of the printer 100 is the service mode OFF and theoperation mode of the printer 200 is the service mode ON (see T54 ofFIG. 2 ).

In T110, the printer 100 is additionally connected to the LAN 4. Next,in T112, a single-purpose CTG is mounted to the printer 100. Thissingle-purpose CTG may be the single-purpose CTG that was mounted to theprinter 200 in T60 of FIG. 2 , or may be a single-purpose CTG that wasnewly sent to the user (i.e., a single-purpose CTG that was sent for theprinter 200 but has not been mounted to the printer 200 yet). Theprinter 100 displays a notification screen SC1 in T114 when accepting anoperation of mounting the single-purpose CTG and determining that theoperation mode of the printer 100 is the service mode OFF. Thenotification screen SC1 includes a message that asks whether to changethe printer used for the flat-rate printing service, a YES button, and aNO button. The user can cause the printer 100 to start a process forchanging the printer used for the flat-rate printing service byoperating the YES button in the notification screen SC1. This improvesthe user convenience.

Here, a comparative example is assumed in which the notification screenSC1 is displayed in response to the printer 100 being turned on, beforethe single-purpose CTG is mounted thereon. In this comparative example,the notification screen SC1 is displayed even when a user who does notwish to receive the flat-rate printing service turns on the printer 100.That is, even when the notification screen SC1 does not need to bedisplayed, the notification screen SC1 is displayed. To the contrary, inthe present embodiment, the printer 100 displays the notification screenSC1 when accepting the operation of mounting the single-purpose CTG. Asdescribed, the single-purpose CTG is a CTG that is shipped when theflat-rate printing service has been concluded, thus a user who does notwish to receive the flat-rate printing service possesses nosingle-purpose CTGs. Therefore, the notification screen SC1 is notdisplayed when a user who does not wish to receive the flat-rateprinting service uses the printer 100. As described, the presentembodiment can prevent the notification screen SC1 from being displayedwhen the notification screen SC1 need not be displayed.

When accepting an operation of selecting the YES button in thenotification screen SC1 in T116, the printer 100 sends a printerchanging request including the printer ID “AAA” of the printer 100 tothe server 10 in T120. The printer changing request is a signal thatrequests the server 10 to change the service-target printer. In T122,the printer 100 displays a QR Code. The QR Code is an image in which aURL1 is coded. The URL1 is stored in advance in the memory 134. The URL1is information indicating a location in the server 10, especially,information indicating a location of input screen data representing aninput screen SC2 for input of account information. The URL1 furtherincludes the printer ID “AAA” of the printer 100 as a query.

In T124, the user captures the QR Code displayed in T122 by using thecamera of the terminal 50. In this case, the terminal 50 obtains theURL1 by decoding the QR Code in T126. Then, the terminal 50 sends a datarequest including the URL1 to the server 10 in T130. The data request isa signal that requests the server 10 to send input screen datarepresenting the input screen SC2.

When receiving the data request from the terminal 50 in T130, the server10 sends the input screen data to the terminal 50 in T132. Here, theserver 10 can obtain the printer ID “AAA” based on the query of the URL1included in the data request. Then, the server 10 determines that theprinter ID “AAA” included in the printer changing request received inT120 is identical to the printer ID “AAA” obtained from the URL1, andcan know that the service-target printer should be changed to theprinter 100 identified by the printer ID “AAA”. In order to executeaccount authentication for the change, the server 10 sends the inputscreen data to the terminal 50 in T132.

When receiving the input screen data from the server 10 in T132, theterminal 50 displays the input screen SC2 represented by the inputscreen data in T134. The input screen SC2 includes a message promptinginput of account information, an input field for a user ID, an inputfield for a PW, and a completion button.

As described, when the YES button in the notification screen SC1 isselected at the printer 100, the QR Code is displayed (T122), the QRCode is captured by the terminal 50 (T124), and the input screen SC2 isdisplayed at the terminal 50. Thus, the user does not have to manuallyinput the URL1 into the terminal 50 to display the input screen SC2 atthe terminal 50. This improves the user convenience.

When accepting, from the user, an operation including input of accountinformation (i.e., the user ID “XXX” and the PW “YYY”) and selection ofthe completion button in T136, the terminal 50 sends the accountinformation to the server 10 in T140.

When receiving the account information from the terminal 50 in T140, theserver 10 executes account authentication in T142. In the presentembodiment, the server 10 determines that the received accountinformation is in the user table 38 (that is, determines that theaccount authentication is successful), and executes a process of FIG. 4. In particular, as described, the server 10 recognizes that thisaccount authentication is for changing the service-target printer to theprinter 100 (see the above description related to T130 and T132).Therefore, when the account authentication is successful, the server 10executes the process of FIG. 4 to change the service-target printer tothe printer 100. Through the process, the server 10 can appropriatelyregister the printer 100 as the service-target printer instead of theprinter 200 identified by the printer ID “BBB” associated with theaccount information (i.e., the user ID “XXX” and the PW “YYY”) for whichthe account authentication was successful.

Here, a comparative example is assumed in which the accountauthentication is not executed when the service-target printer is to bechanged from the printer 200 to the printer 100. In this comparativeexample, if a third party obtains a single-purpose CTG and mounts it toa printer of the third party, the service-target printer may be changedfrom the printer 200 to the printer of the third party. That is, theservice-target printer may be changed without the user of the printer200 not knowing the change. The present embodiment can prevent a thirdparty from changing the service-target printer because the accountauthentication is executed when the service-target printer is to bechanged.

Continuation of Process of FIG. 3; FIG. 4

In T150 of FIG. 4 , the server 10 sends a mode changing request to theprinter 200 by using the XMPP connection. This mode changing request isa signal that requests the operation mode of the printer 200 to bechanged from the service mode ON to the service mode OFF.

When receiving the mode changing request from the server 10 in T150, theprinter 200 changes the service mode flag 238 from ON to OFF in T152.That is, the operation mode of the printer 200 is set to the servicemode OFF. As a result, the printer 200 becomes incapable of executingprinting by using the single-purpose CTG That is, the printer 200 isincapable of executing printing unless a general-purpose CTG is mountedthereon. As described, the operation mode of the printer 200 isautomatically changed to the service mode OFF without the user operatingthe printer 200. This prevents operation modes of two or more printersincluding the printers 100 and 200 that can be used by the same userfrom being the service mode ON simultaneously.

In T154, the server 10 sends a sheet number request to the printer 200using the XMPP connection. The sheet number request is a signal thatrequests the latest cumulative sheet number currently stored in theprinter 200 to be sent.

When receiving the sheet number request from the server 10 in T154, theprinter 200 sends a sheet number response including the printer ID “BBB”of the printer 200 and the cumulative sheet number (“60” in the presentcase) in the memory 234 to the server 10 in T156. Here, the reason whythe cumulative sheet number of the printer 200 is not “50” but “60” isbecause printing has been executed to 10 sheets of print medium afterthe printing of T62 in FIG. 2 was executed at the printer 200. Asdescribed, the processes of T70 and T80 in FIG. 2 are executed, forexample, everyday. The period by which the notification of T70 isexecuted is relatively long. Therefore, another printing may be executedat the printer 200 between the time when the printer 200 sent anotification including the cumulative sheet number to the server 10 andthe time when the next notification is sent. In this case, the latestcumulative sheet number stored in the printer 200 may be different fromthe cumulative sheet number stored in the server 10. In the presentembodiment, a notification including the cumulative sheet number “60”has not been sent to the server 10 yet after the cumulative sheet numberof the printer 200 changed to “60”. Therefore, at the time of T156, thecumulative sheet number “50” and the current sheet number “50” arestored in association with the printer ID “BBB” in the sheet numbertable 40 of the server 10 (see T80 in FIG. 2 ). The process of T156 isexecuted to store the latest cumulative sheet number of the printer 200to the server 10. When the process of T156 is completed, the XMPPconnections established in T50 of FIG. 2 may be disconnected.

When receiving the sheet number response in T156, the server 10 updatesthe user table 38 and the sheet number table 40 in T158. The server 10firstly updates the user table 38. Specifically, the server 10 storesthe printer ID “AAA” included in the printer changing request receivedin T120 of FIG. 3 (i.e., the printer ID “AAA” included in the URL1 inthe data request received in T130), instead of the printer ID “BBB”, inassociation with the account information for which the accountauthentication was successful in T142 of FIG. 3 .

The server 10 further updates the sheet number table 40. Specifically,the server 10 identifies the cumulative sheet number “50” associatedwith the printer ID “BBB” and calculates a difference “10” between theidentified cumulative sheet number “50” and the cumulative sheet number“60” included in the sheet number response of T156. Then, the server 10updates the current sheet number by adding the difference “10” to thecurrent sheet number “50” associated with the printer ID “BBB”. In thisway, the server 10 can properly store the latest current sheet number.The server 10 further updates the cumulative sheet number associatedwith the printer ID “BBB” to “0”. The server 10 further stores theprinter ID “AAA” instead of the printer ID “BBB”.

Processes of T160 to T190 are the same as the processes of T50 to T80 inFIG. 2 except that the printer 100 is used instead of the printer 200and that the current sheet number is updated from “60” (see T158) to“100” in response to the cumulative sheet number “40” being sent to theserver 10.

After that, the printer 100 repeatedly executes printing by using thesingle-purpose CTG. As a result, the color material in thesingle-purpose CTG runs out. In T192, the single-purpose CTG of theprinter 100 is replaced. That is, at the printer 100, the mountedsingle-purpose CTG is detached, and a new single-purpose CTG is mounted.At this time, the printer 100 does not display the notification screenSC1 (T114 in FIG. 3 ) because the operation mode of the printer 100 isthe service mode ON (i.e., the service mode flag 138 is ON). Thisprevents the screen from being unnecessarily displayed.

Effects of First Embodiment

As described, the printer 100 displays the notification screen SC1(T114) when accepting the operation of mounting the single-purpose CTG(T112 in FIG. 3 ) in a state where the printer ID “BBB” of the printer200 and the current sheet number are stored in association with eachother in the server 10. Then, when accepting the operation of selectingthe YES button in the notification screen SC1 from the user (T116), theprinter 100 sends the printer changing request including the printer ID“AAA” of the printer 100 to the server 10 (T120). As a result, in theserver 10, the printer ID “AAA” is stored, instead of the printer ID“BBB”, in association with the current sheet number (T158 in FIG. 4 ).Accordingly, the printer used for the flat-rate printing service (i.e.,service-target printer) can be changed from the printer 200 to theprinter 100.

Here, a comparative example is assumed in which the same operations asin FIG. 2 are performed by the user in order to newly register theprinter 100 as the service-target printer. That is, in the comparativeexample, the user performs the login operation to the server 10 (T10 inFIG. 2 ), the operation of selecting the registration button in theregistration information screen SC0 (T20), and the operation ofinputting a PIN code to the printer 100 (the same operation as T30 tothe printer 100). In this case, the server 10 may store the printer ID“AAA”, instead of the printer ID “BBB”, in association with the accountinformation (i.e., the user ID “XXX”, etc.) (see T42 in FIG. 2 ). If thesame processes as T154 and T156 of FIG. 4 are further executed, theserver 10 may update the sheet number table 40. However, the comparativeexample requires the operation of inputting a PIN code to the printer100, and thus increases the user's workload. To the contrary, thepresent embodiment does not require the user to perform the operation ofinputting a PIN code to the printer 100 (see FIGS. 3 and 4 ). Therefore,the user convenience can be improved as compared to the comparativeexample.

Correspondence Relationships

The printer 100, the printer 200, and the terminal 50 are examples of“first printer”, “second printer”, and “terminal device”, respectively.The display unit 114 is an example of “display unit (and output unit)”.The printer ID “AAA” and the printer ID “BBB” are examples of “firstprinter identification information” and “second printer identificationinformation”, respectively. The flat-rate printing service is an exampleof “service”. The current sheet number is an example of “service-relatedinformation”. The operation of mounting the single-purpose CTG (T112 inFIG. 3 ) and the operation of selecting the YES button in thenotification screen SC1 (T116) are examples of “first predeterminedoperation” and “second predetermined operation”, respectively. The userID “XXX” and the PW “YYY” are an example of “first account information(and second account information)”. The URL1 is an example of “locationinformation”. The service mode ON and the service mode OFF are examplesof “first mode” and “second mode”, respectively. The sheet numberrequest sent in T154 of FIG. 4 and the sheet number response sent inT156 are examples of “information request” and “current information”,respectively.

The process of T114, the process of T120, and the process of T122 inFIG. 3 are examples of “cause the display unit to display a notificationscreen”, “send a printer changing request”, and “cause an output unit tooutput location information” executed by the “first printer”,respectively.

The process of T120 in FIG. 3 and the process of T158 in FIG. 4 areexamples of “receive a printer changing request” and “store the firstprinter identification information” executed by the “server”,respectively. The process of T140 is an example of “receive firstaccount information”. The process of T154, the process of T156, and theprocess of T158 are examples of “send an information request”, “receivecurrent information”, and “update the specific service-relatedinformation”, respectively. The process of T150 is an example of “send amode changing request”.

Second Embodiment; FIG. 5

Next, a second embodiment will be described with reference to FIG. 5 .In the second embodiment, the terminal 50 obtains the URL1 in adifferent manner from the first embodiment. The memory 34 of the server10 stores, in the user table 38, a user ID, a PW, a printer ID, an emailaddress (hereinafter, simply referred to as “MA”), and a CTG ID inassociation with each other. The MA indicates a recipient to which anemail is sent. The email includes the URL1 in its body text. The useraccesses the server 10 by using, for example, the terminal 50 andregisters the account information and the MA in association with eachother in advance in the server 10. The CTG ID is information foridentifying a single-purpose CTG. The CTG ID is stored in the IC chip ofthe single-purpose CTG

Each time the server 10 executes the process for shipping asingle-purpose CTG to the user, the server 10 stores the CTG ID of thesingle-purpose CTG in association with the account information of theuser in the user table 38. In an initial state of FIG. 5 , the server 10has already stored the user ID “XXX”, the PW “YYY”, the printer ID“BBB”, an MA “MA1”, and a CTG ID “ZZZ” in association with each other inthe user table 38.

The process of FIG. 5 is a continuation of the process of FIG. 2 . Aprocess of T210 in FIG. 5 is the same as the process of T110 in FIG. 3 .In T212, a single-purpose CTG is mounted to the printer 100. Since theCTG ID “ZZZ” is stored in the IC chip of this single-purpose CTG, theprinter 100 can read the CTG ID “ZZZ” from the IC chip of thesingle-purpose CTG. Processes of T214 and T216 are the same as theprocesses of T114 and T116 in FIG. 3 . A process of T220 is the same asthe process of T120 in FIG. 3 except that the CTG ID “ZZZ” of thesingle-purpose CTG is included in the printer changing request.

When receiving the printer changing request including the printer ID“AAA” and the CTG ID “ZZZ” in T220, the server 10 identifies the MA“MA1” associated with the CTG ID “ZZZ” included in the printer changingrequest in T222. Then, in T230, the server 10 sends the terminal 50 anemail including the URL1 and the MA “MA1” as a recipient address.

When receiving the email from the server 10 in T230, the terminal 50 candisplay the email. Then, in T232, the user uses the terminal 50 toperform an operation for accessing the URL1 included in the email (e.g.,an operation of clicking the URL1). Processes of T240 to T252 executedin response to that operation are the same as the processes of T130 toT142 in FIG. 3 . As above, the user does not have to manually input theURL1 into the terminal 50 to display the input screen SC2 at theterminal 50. This improves the user convenience. The subsequentprocesses are the same as those of FIG. 4 .

Correspondence Relationships

The CTG ID and the CTG ID “ZZZ” are examples of “cartridgeidentification information” and “specific cartridge identificationinformation”, respectively. The MA “MA1” is an example of “specificemail address”. The process of T230, the process of T240, and theprocess of T242 in FIG. 5 are examples of “send an email”, “receive adata request”, and “send the input screen data” executed by the“server”, respectively.

Third Embodiment; FIG. 6

Next, a third embodiment will be described with reference to FIG. 6 . Inthe third embodiment, the server 10 identifies the email address “MA1”in a different manner from the second embodiment. In the presentembodiment, the server 10 stores no MAs and no CTG IDs in the user table38.

The process of FIG. 6 is a continuation of the process of FIG. 2 .Processes of T310 and T312 in FIG. 6 are the same as the processes ofT110 and T112 in FIG. 3 . The printer 100 displays a notification screenSC3 in T314. The notification screen SC3 includes a message that askswhether to change the printer used for the flat-rate printing service, amessage that prompts input of an MA, an input field for MA, a YESbutton, and a NO button. When accepting an operation of inputting the MA“MA1” into the input field for MA and an operation of selecting the YESbutton in T316, the printer 100 sends a printer changing requestincluding the printer ID “AAA” of the printer 100 and the MA “MA1”inputted in T316 to the server 10 in T320.

By receiving the printer changing request from the printer 100 in T320,the server 10 can identify the email address “MA1” included in theprinter changing request. Processes of T330 to T352 are the same as theprocesses of T230 to T252 in FIG. 5 . As above, the user does not haveto manually input the URL1 into the terminal 50 to display the inputscreen SC2 at the terminal 50. This improves the user convenience.

Correspondence Relationships

The notification screen SC3 is an example of “notification screen”. Theoperation of inputting the MA “MA1” into the input field for MA and theoperation of selecting the YES button in the notification screen SC3 arean example of “second predetermined operation”.

Fourth Embodiment; FIG. 7

Next, a fourth embodiment will be described with reference to FIG. 7 .The fourth embodiment is different from the first embodiment in that theservice-target printer is changed from the printer 200 to the printer100 without input of account information to the terminal 50. The memory34 of the server 10 stores a user ID, a PW, a printer ID, and amigration code in association with each other in the user table 38. Themigration code is information used for authentication to change theservice-target printer.

The process of FIG. 7 is a continuation of the process of FIG. 2 . In aninitial state of FIG. 7 , no migration code is stored in associationwith account information (i.e., the user ID “XXX”, etc.).

When accepting an operation of selecting a migration button from theuser in T410 of FIG. 7 , the printer 200 sends a migration code requestrequesting issuance of a migration code to the server 10 in T412. Themigration code request includes the printer ID “BBB” of the printer 200.

When receiving the migration code request from the printer 200 in T412,the server 10 issues (i.e., generates) a migration code “WWW” and storesthe migration code “WWW” to the user table 38 in association with theprinter ID “BBB” included in the migration code request in T420. Then,in T422, the server 10 sends the migration code “WWW” issued in T420 tothe printer 200.

When receiving the migration code “WWW” from the server 10 in T422, theprinter 200 displays the migration code “WWW” in T424. As a result, theuser can know the migration code “WWW”. In a variant, the printer 200may print the migration code “WWW”.

Processes of T430 and T432 are the same as the processes of T110 andT112 in FIG. 3 . The printer 100 displays a notification screen SC4 inT434. The notification screen SC4 includes a message that asks whetherto change the printer used for the flat-rate printing service, a messagethat prompts input of a migration code, an input field for migrationcode, a YES button, and a NO button. When accepting an operation ofinputting the migration code “WWW” into the input field for migrationcode and an operation of selecting the YES button in T436, the printer100 sends a printer changing request including the printer ID “AAA” ofthe printer 100 and the migration code “WWW” inputted in T436 to theserver 10 in T440.

When receiving the printer changing request including the printer ID“AAA” and the migration code “WWW” from the printer 100 in T440, theserver 10 executes authentication for the migration code in T442.Specifically, the server 10 determines whether or not the migration code“WWW” included in the printer changing request is in the user table 38.In the present embodiment, the server 10 determines that the migrationcode “WWW” is in the user table 38 (i.e., determines that theauthentication is successful), and executes the process of FIG. 4 . Asabove, the user does not have to input account information into theterminal 50 to change the service-target printer. This improves the userconvenience. Further, the server 10 stores the migration code “WWW” andthe printer ID “BBB” in association with each other in the user table38. Therefore, the server 10 can appropriately register the printer 100as the service-target printer instead of the printer 200 identified bythe printer ID “BBB” associated with the migration code “WWW” includedin the printer changing request received in T440.

Correspondence Relationships

The migration code and the migration code “WWW” are examples of“authentication information” and “specific authentication information”,respectively. The migration code request sent in T412 of FIG. 7 is anexample of “authentication information request”. The notification screenSC4 is an example of the “notification screen”. The operation ofinputting the migration code “WWW” to the input field for migration codeand the operation of selecting the YES button in the notification screenSC4 are an example of the “second predetermined operation”. The processof T412, the process of T420, and the process of T422 are examples of“receive an authentication information request”, “store specificauthentication information”, and “send the specific authenticationinformation” executed by the “server”, respectively.

(Variant 1) The “service” is not limited to the flat-rate printingservice described in the above embodiments, and may be, for example, ameasured-rate printing service. The measured-rate printing service is aservice in which the number of printed sheets within a predeterminedperiod is counted every predetermined period (e.g., every month) and afee is charged according to the number of printed sheets.

(Variant 2) The flat-rate printing service is not limited to the aspectsdescribed in the above-described embodiments. For example, the flat-rateprinting service may be a service that allows printing by using a presetnumber of CTGs at a fixed rate every predetermined period. In thisvariant, the number of times CTGs are replaced within the predeterminedperiod is an example of the “service-related information”. In anothervariant, the flat-rate printing service may be a service that allowsprinting by using a preset amount of color material at a fixed rateevery predetermined period. In this variant, an amount of used colormaterial within the predetermined period is an example of the“service-related information”.

(Variant 3) In the above-described embodiments, the “server” isconfigured as the single server 10. However, in a variant, the “server”may be configured of a plurality of servers including a first server anda second server. In this variant, for example, the first server mayexecute the process of T14 in FIG. 2 and the processes of T132 and T142in FIG. 3 . Further, the second server may execute the processes of T24,T42, T50, T52, and T80 in FIG. 2 and the processes of T150, T154, T158,T160, T162, and T190 in FIG. 4 .

(Variant 4) The tables 38 and 40 of the server 10 may be stored in adatabase separate from the server 10. In this variant, the database isan example of “memory” of the “server”.

(Variant 5) The process of the printer 100 outputting the URL1 is notlimited to the display of the QR Code in T122 of FIG. 3 , and may be,for example, a process of displaying a bar code indicating the URL1. Inanother variant, the printer 100 may provide the URL1 to a Near FieldCommunication (NFC) I/F. In this case, the NFC I/F stores the URL1.Therefore, the printer 100 can send the URL1 to the terminal 50 inresponse to the terminal 50 being moved closer to the printer 100. Inthis variant, providing the URL1 to the NFC I/F is an example of “causean output unit to output location information” executed by “firstprinter”. In another variant, the printer 100 may send the URL1 to theterminal 50 via a Bluetooth (BT) (registered trademark) UF. In thisvariant, sending the URL1 via the BT I/F is an example of “cause anoutput unit to output location information” executed by the “firstprinter”.

(Variant 6) In the above-described embodiments, the printer 100 displaysthe notification screen (SC1, SC3, or SC4) when accepting the operationof mounting the single-purpose CTG (T112 in FIG. 3 , T212 in FIG. 5 ,T312 in FIG. 6 , or T432 in FIG. 7 ). In a variant, the printer 100 maydisplay the notification screen when accepting an operation of turningon the printer 100. In this variant, the operation of turning on theprinter 100 is an example of the “first predetermined operation”. Inanother variant, the printer 100 may display the notification screenwhen accepting an operation on a setting button for setting the printer100 as the service-target printer. In this variant, the operation on thesetting button of the printer 100 is an example of the “firstpredetermined operation”.

(Variant 7) Each of the printers 100 and 200 may not be configured touse the two types of CTGs, namely the single-purpose CTG and thegeneral-purpose CTG and may be configured to use only one type of CTG(e.g., the general-purpose CTG; hereinafter referred to as “normalCTG”). In this case, in T60 of FIG. 2 , a normal CTG may be mountedinstead of the single-purpose CTG. Further, if a normal CTG is mountedin T112 of FIG. 3 , a notification screen may be displayed in T114.Generally speaking, the “first printer” is not limited to using both thesingle-purpose color material cartridge and the general-purpose colormaterial cartridge. Further, the “first printer” is not limited toselectively operating in a plurality of modes including the first modeand the second mode.

(Variant 8) After sending the mode changing request to the printer 200in T150 of FIG. 4 , the server 10 may skip the processes of T154 andT156 and execute the process of T158. Specifically, in this variant, theserver 10 may store the printer ID “AAA” in the user table 38 inassociation with the user ID “XXX” and the PW “YYY”, update thecumulative sheet number to “0” in the sheet number table 40 withoutupdating the current sheet number, and store the printer ID “AAA”instead of the printer ID “BBB”. Generally speaking, “send aninformation request,” “receive current information,” and “update thespecific service-related information” executed by the “server” may beomitted.

(Variant 9) The server 10 may not send a mode changing request to theprinter 200 even though a printer changing request is received from theprinter 100. That is, in this variant, the process of T150 in FIG. 4 maybe omitted. Generally speaking, “send a mode changing request” executedby the “server” may be omitted.

(Variant 10) When the operation mode of the printer 100 (or 200) is theservice mode ON, the printer 100 (or 200) may be capable of executingprinting by using the single-purpose CTG and may be capable of executingprinting by using the general-purpose CTG. In this case, the printer 100(or 200) may store the cumulative sheet number of print medium printedby using the single-purpose CTG but may not store the cumulative sheetnumber of print medium printed by using the general-purpose CTG.

(Variant 11) In the above-described embodiments, each of the processesof FIGS. 2 to 7 is implemented by software (e.g., the program 36, 136,236), but at least one of these processes may be implemented by hardwaresuch as a logic circuit.

What is claimed is:
 1. A communication system comprising a first printerand a server, the first printer comprising: a display unit; a firstcommunication interface for communicating with the server; and a firstcontroller, and the server comprising: a second communication interfacefor communicating with the printer; a memory configured to store, foreach of one or more printers, printer identification information foridentifying the printer and service-related information for providing aservice using the printer in association with each other, theservice-related information being obtained by using information receivedfrom the printer; and a second controller, wherein the first controllerof the printer is configured to: in a case where a first predeterminedoperation is accepted in a state where second printer identificationinformation for identifying a second printer and specificservice-related information are stored in association with each other inthe server, cause the display unit to display a notification screen thatprompts a second predetermined operation, the second printer beingdifferent from the first printer, and the second predetermined operationbeing for changing a printer used for the service from the secondprinter to the first printer; and in a case where the secondpredetermined operation is accepted after the notification screen hasbeen displayed, send a printer changing request including first printeridentification information for identifying the first printer to theserver via the first communication interface, wherein the secondcontroller of the server is configured to: in a state where the secondprinter identification information and the specific service-relatedinformation are stored in association with each other in the memory,receive the printer changing request from the first printer via thesecond communication interface; and in a case where the printer changingrequest is received from the first printer, store the first printeridentification information included in the printer changing request,instead of the second printer identification information, in associationwith the specific service-related information.
 2. The communicationsystem as in claim 1, wherein the memory is configured to store, foreach of the one or more printers, the printer identification informationfor identifying the printer, the service-related information forproviding the service using the printer, and account information of auser of the printer in association with each other, the secondcontroller is further configured to: receive first account informationinputted to a terminal device by a user of the first printer from theterminal device via the second communication interface, wherein in acase where the printer changing request is received from the firstprinter and the first account information received from the terminaldevice is identical to second account information stored in the memoryin a state where the second printer identification information, thespecific service-related information, and the second account informationare stored in association with each other in the memory, the secondcontroller is configured to store the first printer identificationinformation included in the printer changing request, instead of thesecond printer identification information associated with the secondaccount information, in association with the specific service-relatedinformation.
 3. The communication system as in claim 2, wherein thefirst controller is further configured to: in the case where the secondpredetermined operation is accepted after the notification screen havebeen displayed, cause an output unit to output location informationindicating a location in the server, the location information indicatinga location of input screen data representing an input screen for inputof the first account information, wherein in response to the locationinformation being outputted, the location information is obtained by theterminal device, the second controller is further configured to: afterthe location information has obtained by the terminal device, send theinput screen data to the terminal device, wherein after the input screendata has sent to the terminal device, the input screen is displayed atthe terminal device.
 4. The communication system as in claim 3, whereinthe output unit is the display unit, and the display unit is caused todisplay a code image in which the location information is coded.
 5. Thecommunication system as in claim 2, wherein the second controller isfurther configured to: in a case where the printer changing request isreceived from the first printer, send an email via the secondcommunication interface, the email including a specific email address asa recipient address and location information indicating a location inthe server, and the location information indicating a location of inputscreen data representing an input screen for input of the first accountinformation; after the email has been sent, receive a data requestincluding the location information, via the second communicationinterface, from the terminal device that received the email; and in acase where the data request is received from the terminal device, sendthe input screen data to the terminal device via the communicationinterface, wherein after the input screen data has been sent to theterminal device, the second controller is configured to receive thefirst account information inputted to the input screen represented bythe input screen data from the terminal device.
 6. The communicationsystem as in claim 5, wherein the memory is configured to store, foreach of the one or more printers, the printer identification informationfor identifying the printer, the service-related information forproviding the service using the printer, the account information of theuser of the printer, an email address of the user, and cartridgeidentification information for identifying a color material cartridgewhich has been shipped to the user in association with each other, theprinter changing request includes the first printer identificationinformation and specific cartridge identification information foridentifying a specific color material cartridge that has been mounted inthe first printer, the email includes the specific email addressassociated with the specific cartridge identification informationincluded in the printer changing request as the recipient address. 7.The communication system as in claim 5, wherein the second predeterminedoperation includes an operation of inputting a specific email address tothe first printer, the printer changing request includes the firstprinter identification information and the inputted specific emailaddress.
 8. The communication system as in claim 1, wherein the secondcontroller is further configured to: receive an authenticationinformation request including the second printer identificationinformation from the second printer via the second communicationinterface; in a case where the authentication information request isreceived from the second printer, store specific authenticationinformation in the memory in association with the second printeridentification information and the specific service-related information;and in the case where the authentication information request is receivedfrom the second printer, send the specific authentication information tothe second printer via the second communication interface, wherein thespecific authentication information is outputted by the second printerin response to the specific authentication information being sent to thesecond printer, the second predetermined operation includes an operationof inputting the specific authentication information to the firstprinter, the printer changing request includes the first printeridentification information and the inputted specific authenticationinformation, and the second controller is configured to store the firstprinter identification information included in the printer changingrequest, instead of the second printer identification informationassociated with the specific authentication information included in theprinter changing request, in association with the specificservice-related information.
 9. The communication system as in claim 1,wherein the first printer is configured to use both a single-purposecolor material cartridge for receiving provision of the service and ageneral-purpose color material cartridge different from thesingle-purpose color material cartridge, and the first predeterminedoperation includes an operation of mounting the single-purpose colormaterial cartridge to the first printer.
 10. The communication system asin claim 9, wherein the first printer is configured to operateselectively in any one of a plurality of modes including a first mode inwhich the first printer is capable of executing printing by using thesingle-purpose color material cartridge and a second mode in which thefirst printer is capable of executing printing by using thegeneral-purpose color material cartridge and is incapable of executingprinting by using the single-purpose color material cartridge, in a casewhere the first printer operates in the second mode and the firstpredetermined operation including the operation of mounting thesingle-purpose color material cartridge to the first printer isaccepted, the first controller is configured to cause the display unitto display the notification screen, and in a case where the firstprinter operates in the first mode and the first predetermined operationincluding the operation of mounting the single-purpose color materialcartridge to the first printer is accepted, the notification screen isnot displayed.
 11. The communication system as in claim 1, wherein thesecond controller is further configured to: in the case where theprinter changing request is received from the first printer, send aninformation request to the second printer via the second communicationinterface; in a case where the information request is sent to the secondprinter, receive current information from the second printer via thesecond communication interface, the current information beinginformation currently stored in the second printer; and in a case wherethe current information is received from the second printer, update thespecific service-related information by using the current information.12. The communication system as in claim 1, wherein each of the firstprinter and the second printer is configured to use both asingle-purpose color material cartridge for receiving provision of theservice and a general-purpose color material cartridge different fromthe single-purpose color material cartridge, each of the first printerand the second printer is configured to operate selectively in any oneof a plurality of modes including a first mode in which the printer iscapable of executing printing by using the single-purpose color materialcartridge and a second mode in which the printer is capable of executingprinting by using the general-purpose color material cartridge and isincapable of executing printing by using the single-purpose colormaterial cartridge, and the second controller is further configured to:in the case where the printer changing request is received from thefirst printer, send a mode changing request to the second printer viathe second communication interface, the mode changing request being forchanging an operation mode of the second printer from the first mode tothe second mode.